Crispin Glover, who appears in the new indie thriller "The Bag Man," talks about doing films to pay for his own art, and why he won't digitize his films.

In movies (notably as George McFly in “Back to the Future”) and TV (such as when he almost kicked David Letterman in the head during an interview in 1989), the actor, filmmaker and artist Crispin Glover has cultivated a screen presence that one could charitably classify as “bizarre.” In person, though, he’s disarmingly approachable, eloquent and talkative. In fact, he talks a lot, banging out multiple questions in one epic response.

Glover is promoting “The Bag Man,” a small thriller with a couple big names, including lead John Cusack and Robert De Niro. His role is supporting: He plays an odd backwater motel clerk who throws Cusack’s hit man off his game when he seeks a room. His reasons for doing the film were simple: “I liked the script,” he says. “The dialogue was particularly well-written.”

“The Bag Man” is one of the few films Glover has done since 2010’s “Hot Tub Time Machine,” also with Cusack. He says that, starting in 2000, he took nearly everything that came his way, so he could finance his own projects. He’s so far directed two films: the surreal “What is It?,” in 2005, and “It is Fine! Everything is Fine,” from 2007.

“From the year 2000 to 2010, most of the films that I was offered I did,” Glover explains. “There were some films that I turned down, but most of the films of that decade, that was essentially what I was offered.”

But in 2010 — the year of Tim Burton’s “Alice in Wonderland,” the biggest moneymaker he’s ever been in — he said he started saying no. “There was something I didn’t like,” he says. “I didn’t work for over a year. And I turned down a lot. Some of it was good money. It’s not a good feeling. But I really did not like what I was being offered.

“I actually like to work a lot. I don’t love not working.”

But Glover says his vocational decisions weren’t purely crass. “I see people writing that with this idea of collecting a paycheck. I really don’t think of it that way,” Glover explains. “I take it very seriously. If I really didn’t think I could accomplish anything a roles at all, I would turn it down. I’ve never gone into a film where I thought, ‘OK, I can’t make this work but I’m going to do it.’”

Glover’s hardly the first person to do films — including “Charlie’s Angels” and its sequel, “Epic Movie” and “Beowulf,” in which he did motion capture work, for his “Back to the Future” boss Robert Zemeckis, as a very odd Grendel — to fund his or her own work.

“I’m not independently wealthy. I’ve always had to work as an actor as a living,” he says. “ He got into the biz at 13, which he did on his own, not because of his parents. (His father, Bruce Glover — who stars in his third directed film, now in the works, although it’s not connected to his two other films — is an actor who appeared as a Bond villain in “Diamonds Are Forever” and in “Chinatown.”) “My parents were supportive of it. But they were not the ones who thought I should do it. I’ve seen people who’ve been forced into the business, and it’s very damaging. That wasn’t the case with me. It was something I wanted.”

These days he’s really on his own: The movies he directs are typically only seen with him in attendance. He tours with his films, which he presents as big multimedia spectacles, with slideshows and often lengthy Q&As, where he offers himself up to the audience’s many queries. He likes dealing with the Alamo Drafthouse chain. “It’s a corporation that’s actually friendly and supportive of filmmakers and cinephiles. Many corporations aren’t. I know — I’ve dealt with them,” he says, chuckling.

None of the films he’s directed have been released on home video, or even been digitized. They exist only as 35mm film prints. “Once something’s digital, it’s over,” he says. “It essentially becomes public domain. It’s illegally public domain, but there are no enforceable laws to stop people from downloading your films.” He says he doesn’t think the film industry can ever recover from the Pandora’s Box of online piracy, so he’s never going to give his work that option. “The only way of truly combating it is to not become a digital entity — to stay in that realm of 35mm prints at theaters.”